Methods for comparing 2D drawings in PDF, image or CAD format

To compare two files that contain 2D drawings or the 3D model of a part, in two different versions, the "COMPARE" tool of the PACK-1A3i uses 3 file comparison methods.

These 3 methods apply equally well :

to PDF files that contain drawings (available on all versions)
to CAD files containing drawings ("Expert" version)
to image files that contain drawings ("Professional" and "Expert" versions)

The 3 methods of comparing drawings are :

Overlay comparison (available with all versions)
Comparison with reference points (available with all versions)
Intelligent Comparison :

TRANSLATION (available with all versions)
TRANSLATION + ROTATION (version "Professionnal" et "Expert")
TRANSLATION + ROTATION + RESIZING (version "Expert").

For each of these three methods we will see :

How they apply to the 3 types of PDF, Image and CAD files
How other software uses (or not) these methods
What are the advantages of the "COMPARE" tool when using these 3 methods

Overlay Comparison

All PDF, image or CAD file comparison software uses this method to detect similarities and differences between 2 file versions.

Most often, this is the only method used by software to compare these files.

In “Drawing Overlay Comparison of PDF, Image or CAD Files” :

We detail the method used in "COMPARE" to make the comparison by superposition.
We compare it to the methods used by other software.

Comparison by reference points

Few programs use this method of file comparison.

Yet this method, when it can be applied to the entire schema or part of the elements of the file, is very efficient and very effective to find the similarities and differences between 2 versions of files.

In "Comparing PDF, Image or CAD drawings by reference points": :

We detail the method used in "COMPARE" for the comparison by reference points.
We compare it to the methods used by other software.

Intelligent Comparison

None of the software we have studied has this comparison which is nevertheless very useful because it allows, in a few seconds, to better determine the similarities and differences of the versions of the files to be compared.